AZState-Administered

SWPPP Requirements in Arizona

Arizona administers its own AZPDES stormwater program, authorized by the EPA. The Arizona Department of Environmental Quality (ADEQ) issues the state Construction General Permit and handles all permitting, compliance, and enforcement. Arizona's unique desert climate creates distinctive stormwater challenges — extended dry periods followed by intense monsoon storms from June through September. The state's rapid growth, particularly in the Phoenix and Tucson metropolitan areas, means thousands of active construction sites must maintain SWPPP compliance. Arizona also has stricter dust control requirements through county-level agencies (particularly Maricopa County) that often overlap with SWPPP obligations.

Arizona SWPPP Key Facts

✓Arizona administers its own AZPDES program — file NOIs with ADEQ, not EPA
✓Rain event inspection threshold is 0.5 inches (higher than federal 0.25 inches)
✓NOI fee is $250 with a $250 annual permit fee
✓CGP permit number AZG2025-001 (replaced AZG2020-001, which ended August 28, 2025)
✓Monsoon season (June 15–September 30) is the highest-risk period
✓Maricopa County has separate dust control permit requirements (Rule 310/310.01)
✓Projects near Outstanding Arizona Waters face additional BMP requirements
✓ADEQ myDEQ portal is used for electronic NOI filing and compliance tracking

Arizona County Map

6 MS4 jurisdictions · 15 counties

MS4 Jurisdictions

Standard Counties

CountyMS4 JurisdictionSelected

Administering Agency

Agency: Arizona Department of Environmental Quality (ADEQ)
Phone: (602) 771-2300
Email: stormwater@azdeq.gov
Website: ADEQ Stormwater Program

Permit Details

Permit Name: AZPDES Construction General Permit (CGP)
Permit Number: AZG2025-001
Effective Date: 2025-08-29
Expiration Date: 2030-08-28
Permit Document: View Current Permit

SWPPP Thresholds & Triggers

Acreage Threshold: 1 acre

Inspection Requirements

Inspection Frequency: Every 7 calendar days, or every 14 days with qualifying rain event inspections
Rain Event Threshold: 0.5 inches within 24 hours
Certified Inspector: Not required by state

Penalties & Enforcement

Max Civil Penalty (Per Day): $25,000
Criminal Penalties: Class 2 misdemeanor for negligent violations. Knowing violations may be prosecuted as Class 6 felony under Arizona Revised Statutes.

Permit Fees

NOI Filing Fee: $250
Annual Fee: $250/year
NOT Filing Fee: No separate fee
Other Fees: Expedited NOI processing available for additional fee. Fee waivers may be available for small public projects.

How Arizona Differs from Federal Requirements

⚠State-administered AZPDES program — file with ADEQ, not EPA
⚠Higher rain event inspection threshold: 0.5 inches vs. federal 0.25 inches
⚠State NOI fee of $250 + $250 annual fee (federal CGP has no fee)
⚠Outstanding Arizona Waters designation may require individual permit instead of CGP
⚠Maricopa County dust control permits are an additional layer beyond SWPPP
⚠Maximum civil penalty is $25,000/day (vs. federal $64,618/day)

SWPPP Tips for Arizona

➤File your NOI through ADEQ's myDEQ online portal — allow 7-14 days for processing
➤In Maricopa County, you likely need BOTH a SWPPP and a dust control permit — coordinate early
➤Size sediment basins for monsoon-intensity events (2-year, 24-hour storm at minimum)
➤Stabilize disturbed areas within 14 days of final grading — desert soils erode rapidly once disturbed
➤Keep extra BMPs stockpiled on-site from June through September for emergency monsoon repairs
➤Photo-document all inspections — ADEQ requires photographic evidence in compliance records
➤If you were covered under AZG2020-001, confirm your NOI and SWPPP meet AZG2025-001 conditions (ADEQ public notices detail transition requirements)
➤Coordinate with local jurisdictions (Maricopa, Pima, Pinal counties) for additional local requirements

Arizona SWPPP FAQs

How do I file an NOI in Arizona?+

File your NOI electronically through ADEQ's myDEQ portal at https://www.azdeq.gov/programs/water-quality-programs/stormwater The filing fee is $250, and you should allow 7-14 days for processing. You must have NOI authorization before commencing construction. ADEQ also accepts paper NOI forms by mail for those unable to use the electronic system.

Do I need a separate dust control permit in Arizona?+

In Maricopa County, yes — the Maricopa County Air Quality Department requires a separate dust control permit under Rule 310 for any earth-moving activity on 0.1 acres or more. Pima County has similar requirements. These are separate from your SWPPP but your erosion control BMPs often serve dual purposes.

Why is Arizona's rain event threshold different from federal?+

Arizona's CGP uses a 0.5-inch rain event threshold (vs. the federal 0.25-inch), reflecting the state's arid climate where most precipitation comes as intense, short-duration monsoon events. This higher threshold prevents unnecessary inspections from light, brief showers that don't produce significant runoff in desert conditions.

What are Outstanding Arizona Waters and how do they affect my SWPPP?+

Outstanding Arizona Waters (OAWs) are high-quality water bodies designated for additional protection under Arizona's Surface Water Quality Standards. If your project discharges to or is near an OAW, your SWPPP must include enhanced BMPs and monitoring. ADEQ may require individual permit coverage instead of the CGP for projects near OAWs.

What unique BMPs work best in Arizona's desert climate?+

Arizona sites benefit from: rock check dams (more durable than straw in desert heat), gravel bag barriers (replace silt fence on rocky soils), soil tackifiers and polymers for dust/wind erosion, concrete washout areas with evaporation-based designs, and robust sediment basins sized for monsoon intensity. Traditional BMPs like silt fence degrade rapidly in extreme heat and UV.

Arizona County SWPPP Jurisdictions

Use the county map at the top of this page to jump to a specific jurisdiction. Counties marked MS4 require an additional local construction stormwater permit on top of the state CGP.

MS4 Counties — Local Permit Overlay Required

Coconino County

MS4 Active

FIPS 04005

Local MS4 Authority

City of Flagstaff Stormwater

A local MS4 stormwater construction permit is required in addition to the state CGP for sites within this jurisdiction.

Largest county in the contiguous US by area. Flagstaff has a Phase II MS4 permit — local stormwater ordinance applies within city limits. Grand Canyon watershed — extreme sensitivity. Navajo Nation and Hopi Tribe lands within county boundaries require tribal environmental consultation.

Yavapai County

MS4 Active

FIPS 04025

Local MS4 Authority

City of Prescott Engineering/Stormwater

A local MS4 stormwater construction permit is required in addition to the state CGP for sites within this jurisdiction.

Prescott metro area (Prescott, Prescott Valley, Chino Valley) is a fast-growing construction market. Prescott has a Phase II MS4. Verde River watershed — sensitive cold-water fishery. Granite Dells area requires careful WOTUS/wetland identification.

Maricopa County

MS4 Active

FIPS 04013

Local MS4 Authority

Maricopa County Flood Control District

A local MS4 stormwater construction permit is required in addition to the state CGP for sites within this jurisdiction.

Phoenix metro — one of the fastest-growing construction markets in the US. Maricopa County Flood Control District has a Phase I MS4 permit covering unincorporated areas. City of Phoenix, Scottsdale, Mesa, Tempe, Chandler, Gilbert, Glendale, Peoria, and dozens of other MS4-permitted municipalities each have local stormwater construction requirements. ADEQ actively enforces AZPDES in this county. Dust control permits from Maricopa County Air Quality Department are required separately for disturbed soil. Monsoon season (June–September) dramatically increases inspection frequency requirements.

Pinal County

MS4 Active

FIPS 04021

Local MS4 Authority

City of Casa Grande / City of Maricopa Stormwater

A local MS4 stormwater construction permit is required in addition to the state CGP for sites within this jurisdiction.

Fast-growing exurban corridor between Phoenix and Tucson. Casa Grande and Maricopa (City) have active MS4 programs. Significant new residential construction. San Pedro River and Santa Cruz River headwaters in the south.

Yuma County

MS4 Active

FIPS 04027

Local MS4 Authority

City of Yuma Stormwater Program

A local MS4 stormwater construction permit is required in addition to the state CGP for sites within this jurisdiction.

Yuma has a Phase II MS4. Colorado River and Gila River confluence — USACE Section 404 applies. Agricultural irrigation drainage creates complex stormwater chemistry. MCAS Yuma federal lands have separate environmental compliance.

Pima County

MS4 Active

FIPS 04019

Local MS4 Authority

Pima County Regional Flood Control District

A local MS4 stormwater construction permit is required in addition to the state CGP for sites within this jurisdiction.

Tucson metro — second-largest construction market in AZ. Pima County RFCD and City of Tucson both have active MS4 programs with local stormwater construction requirements. Santa Cruz River and Rillito River — USACE floodplain coordination required. AZPDES actively enforced. Tucson's monsoon season creates intense but localized storm events requiring rapid BMP response.

All Other Arizona Counties — State CGP Only

Navajo County

FIPS 04017

Large portions of this county are Navajo Nation and White Mountain Apache tribal lands with sovereign environmental jurisdiction — federal/state AZPDES may not apply on tribal lands. Show Low and Pinetop areas. Little Colorado River drainage.